Attributing eCO2 data to 3D Models (Revit-focus): State of Practice?

There are numerous developments going on in analyzing embodied carbon of a 3D model, especially in the building structures world. Companies are building their own tools, or using proprietary LCA tool Revit integrations to assess the eCO2 of 3D models at various stages of development.
There are too many out there for me to manually evaluate them all; but there is a large enough community of people who have tested them or use them already, so this is why I’m posting:

How do these tools actually deal with element data? And/or how do different consultants deal with associating the right data with their models?

At the heart of every different eCO2 analysis process, I believe we are determining a Mass for every element, then multiplying by an eCO2 rate. I’m building something from first principles, to maintain full control over the analysis. I’m exporting to Excel, a specific set of parameters for different types of elements, e.g. Concrete Beams, Concrete Columns, Concrete Floors, Steel Beams, Steel —, etc. the list goes on, because (as anyone dealing with Revit knows) different element types and families have different parameter complexities.

It would be a big imposition on the Revit modelling process to make sure technicians are getting this data correct when initially modelling our buildings. And things like concrete on metal deck, and reinforcement rates in concrete – these are all significant enough to warrant a degree of data refinement (e.g. kg of concrete per m2 of deck, and kg of reinforcement per m3 of concrete), but impractical to get that data into the model at the initial modelling stage. So my current plan is to to export a snapshot of the model element data at a particular point in time, manually assign the necessary data to individual elements (in custom parameters, using Excel), then BIM Link (a Revit add-in) can push it back to Revit.

This is not as smart a process as I believe it can be; it requires a good deal of manual post-processing of just a snapshot of the Revit model data at a point in time. How are others achieving similar? Or are they? Do existing proprietary tools do the same? Or do they do even less (i.e. less refined data)?

All thoughts and input welcome.

Revit could technically hold all the necessary data within its element properties but it is not currently used to its full BIM potential. Users of Revit mostly use it as a 3D modeling tool, not as a full-out BIM tool. There is a lot of effort that developers of Revit-LCA plugins like Tally, OneClick, or Beacon do to take advantage of the element properties that do get defined, and include some default values for stuff like typical rebar per volume of concrete, deck profiles, mullion profiles, steel section profiles, paint and coating thicknesses, etc. You can build your own database of CO2e values per mass (or volume, or area, or length) of a material or product, collect your own tables of default shapes and quantities and then use something like Dynamo to automate the data exchange process between Revit and external databases. But really, a more wide-reaching solution would be to actually standardize BIM modeling, develop a database of standard materials and elements with predefined and linked properties to LCA data, and store it in a public repository for anyone to use (kind of like the native Revit materials library). Architects and engineers could then use these default/template models as a starting point and be set for LCA success. Without this there is a lot of extra labor and room for error in BIM-based LCAs.

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Thanks for the response Vaclav,

Much of the insight reaffirms what I suspected about Revit’s capacity for data versus the current state of practice, and the challenges that have to be overcome.

As for our own carbon database: That side of the problem is solved in my case :slight_smile: We have a workbook setup that is a curated collection, largely based on the ICE v3 database (commonly used in the UK)